Notably, HBO Go is not yet on Fire TV, but an Amazon spokesman said the company is working with the pay-TV network to make it available. To be sure, Amazon Fire TV users would still need a pay-TV subscription to HBO to access HBO Go.

The long-anticipated device is also the latest platform for Amazon's own Netflix rival Prime Instant Video, which the company hopes will attract people to its $99-a-year Prime service that gives subscribers free two-day shipping and access to its on-demand streaming library as well as original shows.

Amazon has been making deals with programmers to get more content for its service. It recently secured exclusive rights to stream the popular Fox show "24" and the TV movie "24: Redemption" ahead of the launch of "24: Live Another Day."

The company has also tried to rival Netflix by making its own shows for Prime Instant, including the political comedy "Alpha House" starring John Goodman, which was renewed last month for a second season. In addition, Amazon has greenlighted six new pilots for full seasons, which will become available later this year.

While the Prime Instant offerings are improving, that may not be enough to get people to sign up, said Michael Pachter, an analyst at Wedbush Securities, who covers Amazon.

"The content is getting much better, but it isn’t used by many Prime members, since so many people use Netflix already," Pachter said in an email.

Pachter was generally unimpressed with the Fire TV roll-out, calling the box a "me-too" device with pricing similar to Apple TV and Roku. "I don’t see this as helping them in any way," he said.

Shares of Amazon were little changed Wednesday. At the close of trading on the Nasdaq, Amazon's stock price was down $1.03, or 0.30%, to $341.96 a share. Shares of Netflix fell $1.81, or 0.50%, to $362.88 a share.